ObjectiveTo study the external biocompatibility bewteen the mouse induced pluripotent stem cells (miPSCs) and poly-3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBHHx). MethodsAfter we recovered and subcultured miPSCs, we divided them into two groups. There was one group cultured with material of PHBHHx films outside the body. We observed the adhesive pattern of miPSCs on film by fluorescence of 4, 6-diamidino-2-phenylindole (DAPI) staining. The cell vitality was detected by cell counting kit-8 (CCK-8). The morphology of miPSCs attached on the film was visualized under scanning electron microscope (SEM). We used the traditional petri dish to culture miPSCs and detect the cell activity by CCK-8. ResultsMiPSCs can adhere and proliferate on PHBHHx films. The result of cell vitality which detected by CCK-8 showed that there was a statistical difference in OD value between culturing on PHBHHx films and traditional cultivation (0.617±0.019 vs. 0.312±0.004, P < 0.05). ConclusionThere are adhesion and proliferation on the surface of cells patch made by miPSCs co-culturing with PHBHHx film. Compared with traditional culturing in the cell culture dish, culturing in PHBHHx films have great advantages in the process of adhesion and proliferation. PHBHHx can be used as one of the scaffold for stem cells treating various disease.
Objective To review the application of urine derived stem cells (USCs) in regeneration of musculoskeletal system. Methods The original literature about USCs in the regeneration of musculoskeletal system was extensively reviewed and analyzed. Results The source of USCs is noninvasive and extensive. USCs express MSCs surface markers with stable proliferative and multi-directional differentiation capabilities, and are widely used in bone, skin, nerve, and other skeletal and muscle system regeneration fields and show a certain repair capacity. Conclusion USCs from non-invasive sources have a wide application prospect in the regeneration of musculoskeletal system, but the definite biological mechanism of its repair needs further study.
ObjectiveTo construct bone morphogenetic protein 2 (BMP-2) gelatin/chitosan hydrogel sustained-release system, co-implant with induced pluripotent stem cells (iPS) derived mesenchymal stem cells (MSCs) to hydroxyapatite (HA)/zirconium dioxide (ZrO2) bio porous ceramic foam, co-culture in vitro, and to explore the effect of sustained-release system on osteogenic differentiation of iPS-MSCs.MethodsBMP-2 gelatin/chitosan hydrogel microspheres were prepared by water-in-oil solution. Drug encapsulation efficiency, drug loading, and in vitro sustained release rate of the microspheres were tested. HA/ZrO2 bio porous ceramic foam composite iPS-MSCs and BMP-2 gelatin/chitosan hydrogel sustained release system co-culture system was established as experimental group, and cell scaffold complex without BMP-2 composite gelatin/chitosan hydrogel sustained release system as control group. After 3, 7, 10, and 14 days of co-culture in the two groups, ALP secretion of cells was detected; gene expression levels of core binding factor alpha 1 (Cbfa1), collagen type Ⅰ, and Osterix (OSX) were detected by RT-PCR; the expression of collagen type Ⅰ was observed by immunohistochemical staining at 14 days of culture; and cell creep and adhesion were observed by scanning electron microscopy.ResultsBMP-2 gelatin/chitosan hydrogel sustained-release system had better drug encapsulation efficiency and drug loading, and could prolong the activity time of BMP-2. The secretion of ALP and the relative expression of Cbfa1, collagen type Ⅰ, and OSX genes in the experimental group were significantly higher than those in the control group at different time points in the in vitro co-culture system (P<0.05). Immunohistochemical staining showed that the amount of fluorescence in the experimental group was significantly more than that in the control group, i.e. the expression level of collagen type Ⅰ was higher than that in the control group. The cells could be more evenly distributed on the materials, and the cell morphology was good. Scanning electron microscopy showed that the sustained-release system could adhere to cells well.ConclusioniPS-MSCs have the ability of osteogenic differentiation, which is significantly enhanced by BMP-2 gelatin/chitosan hydrogel sustained-release system. The combination of iPS-MSCs and sustained-release system can adhere to the materials well, and the cell activity is better.
Objective To explore the role of over-expression of TBX3 and TBX18 in inducing human induced pluripotent stem cells (HiPS) to enrich and differentiate into sinoatrial node-like cells. Methods The expression of stemness markers OCT3/4, SOX2, and NANOG in HiPS was detected by real-time fluorescence quantitative PCR (qRT- PCR), and compared with human embryonic stem cells (hESCs). Immunofluorescence staining was used to observe the expression of HiPS stemness markers OCT3/4, NANOG, SSEA4, and TRA-1-60. The HiPS were directional differentiated into cardiomyocytes, the expressions of ISL1, NK2 homeobox 5 (NKX2-5), ACTN1, and TNNT2 were detected by qRT-PCR, and human adult cardiomyocytes (hACM) were used as positive control. Immunofluorescence staining was used to observe the expressions of NKX2-5, cardiac troponin (cTnT), α-actinin, atria myosin light chain 2A (MLC-2A), and ventricular myosin light chain 2V (MLC-2V). The positive rate of α-actinin was detected by flow cytometry. On the 3rd day after HiPS were differentiated into cardiomyocytes (mesodermal stage), lentiviral over-expressions of sinoatrial node-related genes TBX3 and TBX18 were carried out for 21 days. The relative expressions of specific markers TBX3, TBX18, SHOX2, NKX2-5, HCN4, and HCN1 in sinoatrial node cells were detected by qRT-PCR, and compared with enhanced green fluorescent protein blank virus. Results OCT3/4, SOX2, and NANOG were highly expressed in HiPS and ESCs, and there was no significant difference in the relative expression of each gene (P>0.05); OCT3/4 and NANOG were specifically distributed in the nucleus of HiPS, while SSEA4 and TRA-1-60 were distributed in the cell membrane. The relative expressions of ISL1 gene at 5, 7, 21, and 28 days and NKX2-5 gene at 7, 21, and 28 days of HiPS differentiation into cardiomyocytes were significantly higher than those of hACM (P<0.05), and the relative expressions of ACTN1 and TNNT2 genes at 3, 5, 7, and 21 days of HiPS differentiation into cardiomyocytes were significantly lower than those of hACM (P<0.05). NKX2-5 was expressed in most of the nuclei, cTnT and α-actinin, MLC-2A and MLC-2V signals were localized in the cytoplasm, presenting a texture-like structure of muscle nodules. Flow cytometry results showed that HiPS was successfully induced to differentiate into cardiomyocytes. The expressions of TBX18, SHOX2, HCN4, and HCN1 in the over-expression TBX3 group were up-regulated when compared with the control group, and difference in the relative expression of SHOX2 gene was significant (P<0.05); the relative expression of NKX2-5 gene was lower than that in the control group, but there was no significant difference (P>0.05). There was no significant difference in the relative expression of each gene between the over-expressed TBX18 group and the control group (P>0.05). Conclusion HiPS and hESCs have similar pluripotency, and we have established a stable method for maintaining and culturing the stemness of HiPS. A technological platform for the efficient differentiation of HiPS into cardiomyocytes has been successfully established. Although TBX3 and TBX18 do not play a significant role in promoting the enrichment and differentiation of HiPS into sinoatrial node-like cells, TBX3 shows a certain promoting trend, which can be further explored in the future.
ObjectiveTo explore the role of joint regulation of Wnt and bone morphogenetic protein (BMP) signaling pathways in the differentiation of human induced pluripotent stem cells (hiPSCs) into cardiomyocytes.MethodsHiPSCs were cultured and observed under inverted phase contrast microscope. Immunofluorescence staining was used to observe the expressions of hiPSCs pluripotent markers (OCT3/4, NANOG, and TRA-1-60). HiPSCs were passaged which were taken for subsequent experiments within the 35th passage. When the fusion degree of hiPSCs was close to 100%, the CHIR99021 (Wnt pathway activator) was added on the 0th day of differentiation. Different concentrations of IWP4 (inhibitor of Wnt production) were added on the 3rd day of differentiation, and the best concentration of IWP4 was added at different time points. The optimal concentration and the best effective period of IWP4 were obtained by detecting the expression of troponin T (TNNT2) mRNA by real-time fluorescence quantitative PCR. Then, on the basis of adding CHIR99021 and IWP4, different concentrations of BMP-4 were added on the 5th day of differentiation, and the best concentration of BMP-4 was added at different time points. The optimal concentration and best effective period of BMP-4 were obtained by detecting the expression of TNNT2 mRNA. Finally, hiPSCs were divided into three groups: Wnt group, BMP group, and Wnt+BMP group. On the basis of adding CHIR99021 on the 0th day of differentiation, IWP4, BMP-4, and IWP4+BMP-4 were added into Wnt group, BMP group, and Wnt+BMP group respectively according to the screening results. Cells were collected on the 7th and the 15th days of differentiation. The expressions of myocardial precursor cell markers [ISL LIM homeobox 1 (ISL1), NK2 homeobox 5 (NKX2-5)] and cardiomyocyte specific markers [myocyte enhancer factor 2C (MEF2C), myosin light chain 2 (MYL2), MYL7, and TNNT2] were detected by real-time fluorescent quantitative PCR. Cells were collected on the 28th day of differentiation, and the expression of cardiac troponin T (cTnT) was detected by flow cytometry and immunofluorescence staining.ResultsThe results of cell mophology and immunoflurescence staining showed that the OCT3/4, NANOG, and TRA-1-60 were highly expressed in hiPSCs, which suggested that hiPSCs had characteristics of pluripotency. The optimal concentration of IWP4 was 10.0 μmol/L (P<0.05) and the best effective period was the 3rd day (P<0.05) in inducing hiPSCs to differentiate into cardiomyocytes. The optimal concentration of BMP-4 was 20.0 ng/mL (P<0.05) and the best effective period was the 3rd day (P<0.05). The relative expressions of ISL1, NKX2-5, MEF2C, MYL2, MYL7, and TNNT2 mRNAs, the positive expression ratio of cTnT detected by flow cytometry, and sarcomere structure detected by immunofluorescence staining of Wnt+BMP group were superior to those of Wnt group (P<0.05).ConclusionJoint regulation of Wnt and BMP signaling pathways can improve the differentiation efficiency of hiPSCs into cardiomyocytes.
ObjectiveTo provide experimental data and theoretical support for further studying the maturity of cardiac patches in other in vitro experiments and the safety in other in vivo animal experiments, through standard chemically defined and small molecule-based induction protocol (CDM3) for promoting the differentiation of human induced pluripotent stem cells (hiPSCs) into myocardium, and preliminarily preparing cardiac patches. MethodsAfter resuscitation, culture and identification of hiPSCs, they were inoculated on the matrigel-coated polycaprolactone (PCL). After 24 hours, the cell growth was observed by DAPI fluorescence under a fluorescence microscope, and the stemness of hiPSCs was identified by OCT4 fluorescence. After fixation, electron microscope scanning was performed to observe the cell morphology on the surface of the patch. On the 1st, 3rd, 5th, and 7th days of culture, the cell viability was determined by CCK-8 method, and the growth curve was drawn to observe the cell growth and proliferation. After co-cultured with matrigel-coated PCL for 24 hours, hiPSCs were divided into a control group and a CDM3 group, and continued to culture for 6 days. On the 8th day, the cell growth was observed by DAPI fluorescence under a fluorescence microscope, and hiPSCs stemness was identified by OCT4 fluorescence, and cTnT and α-actin for cardiomyocyte marker identification. ResultsImmunofluorescence of hiPSCs co-cultured with matrigel-coated PCL for 24 hours showed that OCT4 emitted green fluorescence, and hiPSCs remained stemness on matrigel-coated PCL scaffolds. DAPI emitted blue fluorescence: cells grew clonally with uniform cell morphology. Scanning electron microscope showed that hiPSCs adhered and grew on matrigel-coated PCL, the cell outline was clearly visible, and the morphology was normal. The cell viability assay by CCK-8 method showed that hiPSCs proliferated and grew on PCL scaffolds coated with matrigel. After 6 days of culture in the control group and the CDM3 group, immunofluorescence showed that the hiPSCs in the control group highly expressed the stem cell stemness marker OCT4, but did not express the cardiac markers cTnT and α-actin. The CDM3 group obviously expressed the cardiac markers cTnT and α-actin, but did not express the stem cell stemness marker OCT4. ConclusionhiPSCs can proliferate and grow on matrigel-coated PCL. Under the influence of CDM3, hiPSCs can be differentiated into cardiomyocyte-like cells, and the preliminary preparation of cardiac patch can provide a better treatment method for further clinical treatment of cardiac infarction.
Objective To study the differentially expressed genes (DEG) during the differentiation of human induced pluripotent stem cells (hiPSC) and human embryonic stem cells (hESC) into pericytes and endothelial cells, and to identify key molecules and signaling pathways that may regulate this differentiation process. MethodshiPSC and hESC were selected and expanded using mTeSR medium. A "two-step method" was used to induce the differentiation of hiPSC and hESC into pericytes and endothelial cells. Pericytes were identified using immunofluorescence staining, while endothelial cells were isolated and identified using flow cytometry. Total RNA samples were extracted on days 0, 4, 7, and 10 of differentiation and consistently significant DEGs were screened. Gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) signal pathway enrichment analysis were performed on the screened DEGs. ResultsBoth hiPSCs and hESCs successfully differentiated into pericytes and endothelial cells under induction conditions. Transcriptome sequencing results showed that with the extension of differentiation time, the DEGs in hiPSCs and hESCs were significantly upregulated or downregulated, following a generally consistent trend. During the differentiation process, marker genes for pericytes and endothelial cells were significantly upregulated. A total of 491 persistent DEGs were detected in both hiPSC and hESC, with 164 unique to hiPSCs and 335 to hESCs, while 8 DEGs were co-expressed in both cell lines. Among these, SLC30A3, LCK, TNFRSF8, PRDM14, and GLB1L3 showed sustained downregulation, whereas CLEC18C, CLEC18B, and F2RL2 exhibited sustained upregulation. GO enrichment analysis revealed that DEGs with sustained upregulation were primarily enriched in terms related to neurogenesis, differentiation, and developmental proteins, while DEGs with sustained downregulation were enriched in terms related to membrane structure and phospholipid metabolic processes. KEGG pathway analysis showed that upregulated genes were primarily enriched in cancer-related pathways, pluripotency regulatory pathways, the Wnt signaling pathway, and the Hippo signaling pathway, whereas downregulated genes were predominantly enriched in metabolism-related pathways. ConclusionsDuring the differentiation of hiPSC and hESC into pericytes and endothelial cells, 8 DEGs exhibit sustained specific expression changes. These changes may promote pericyte and endothelial cell differentiation by activating the Wnt and Hippo pathways, inhibiting metabolic pathways, releasing the maintenance of stem cell pluripotency, affecting the cell cycle, and inhibiting cell proliferation.